alt Hacker News> Where did they come up with 10 to 25% savings?
I did really rough math and a hypothetical 200W panel getting 100% sun for 5 hours per day (1 kW/hr) would net you a whopping ~$9.30 in savings per month. We're paying something like $0.31 per kW/hr in NYC and it's a lot of money right now.
Did your calculations account for the suboptimal angle of the panels in most balcony solar setups? Most calculators assume the panels are at an optimal angle or on a roof pitch, not vertical like the image in the article.
A setup like the image in the article is going to get much lower than optimal efficiency because the panel is mounted vertically. She could be netting closer to $2-3 dollars per month or even less depending on which way she’s facing.